Arthrogryposis, mental retardation and seizures

Gene : SLC35A3

What is arthrogryposis, mental retardation and seizures?

Arthrogryposis, mental retardation and seizures (AMRS) is a rare inherited disorder. Arthrogryposis is a condition where the baby is born with multiple joint contractures in their arms and/or legs that cause them to be bent in a certain direction. Infants with AMRS may also have limb malformations, weak muscle tone and a small head. Affected children typically have intellectual disability and some autistic features as well as seizures. There is no cure for AMRS but medical surveillance and care may improve some symptoms and overall condition of life. AMRS is caused by pathogenic variants in the SLC35A3 gene.

How is arthrogryposis, mental retardation and seizures inherited?

AMRS is inherited in an autosomal recessive manner. This type of inheritance requires the presence of two copies of a pathogenic variant for a person to have the genetic disease. Both parents must be carriers of a pathogenic variant in the gene in order to be at risk to have an affected child. The child must inherit a pathogenic variant from each carrier parent in order to be affected. There is a 1 in 4 chance that a baby will inherit two mutated copies of the gene and be affected when both parents are carriers.

What does it mean to be a carrier?

There are generally no signs or symptoms associated with being a carrier for AMRS. However, the risk to have a child affected with AMRS is increased. Testing of reproductive partners is recommended for carriers of AMRS.

How common is arthrogryposis, mental retardation and seizures?

AMRS is a rare disorder but seen more frequently in the Ashkenazi Jewish population, which has a 1 in 373 carrier frequency.

Family References and Resources

The following websites may be informative: Genetic Home Reference: SLC35A3 (

Clinician References
What is Analyzed?
  • Full gene sequencing
Affected Systems




Carrier Rates
Detection Rate
Carrier Frequency
Ashkenazi Jewish 99% 1 in 205
General Population 99% 1 in 500

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